The field of the invention is broadly refrigeration but it also relates to the control of body temperature.
The most common method for providing cooling to a person in a hot or unventilated area is to cool air by normal refrigeration and to pass the cooled air into an area adjacent the body to be cooled.
Liquid cooling apparatus is also known, and one such device is shown in the Jennings U.S. Pat. No. 3,289,748. A liquid, such as water, is passed through the tubes and then the liquid is cooled in a heat exchanger. Similarly, in the Feher U.S. Pat. No. 3,411,156, flexible tubing is provided for carrying a cooling liquid within a space garment. Another liquid-cooled garment is shown in the Crocker U.S. Pat. No. 3,430,688 where a pump and heat exchanger moves and cools the liquid passing through the tubing. In the Troyer U.S. Pat. No. 3,610,323, a garment has a tube therein, which tube includes capillaries. A chemical such as Freon is pumped into the tubes and escapes through the capillaries to evaporate and cause a cooling effect to the wearer. The Kramer U.S. Pat. No. 4,566,455 shows a scalp cover through which a coolant liquid is pumped. The coolant liquid is cooled by an ice and water mixture. In the Cahn U.S. Pat. No. 4,662,433, a blanket is provided with internal ducts through which a stable foam is circulated. The foam is heat exchanged with ice or an ice water reservoir or a cooled refrigerant. The Sauder U.S. Pat. No. 3,916,911 shows a cooling collar which includes a ductal metal coil, such as copper, through which a refrigerant such as Freon is circulated. Lastly, the Sauder U.S. Pat. No. 4,170,998 also shows a portable cooling apparatus which circulates a refrigerant through flexible tubing and from there into an auxiliary evaporator and back to a conventional compressor and condenser.
All of the above-discussed units are too bulky to be used in many confined situations such as a race car or within a suit completely sealed to handled toxic fumes. In this sort of an application, light weight and wearer comfort are very important.